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Functional foods

Research on "functional foods" is complicated by the lack of an agreed-upon definition.

From the Field

What are functional foods?


Functional foods


Functional foods are conventional (whole) or modified foods that provide health benefits in addition to basic nutrition. Currently, there is no official definition or regulatory standard for functional foods in the United States. Claims can be questionable due to limited evidence and mixed findings.


In the 1980s the Japanese government began to regulate the analysis and development of foods supplemented with ingredients for medical or health benefits, which they call Foods for Specified Health Use (FOSHU), the predecessors of what are considered “functional foods” in America today. The FOSHU system went into effect in 1991, whereupon 13 food products were approved. Japan still has the only regulatory statute in the world that covers functional foods.  Today there are numerous products that are marketed in the U.S. as “functional foods” based on their health claims, but there is no official or universally accepted U.S. definition. The Institute of Medicine’s Food and Nutrition Board defines functional foods as “any food or food ingredient that may provide a health benefit beyond the traditional nutrients it contains.” The American Dietetic Association expands the definition by 1) including the intention of functional foods to benefit health and 2) offering four categories of functional foods (conventional, modified, medical, and foods for special dietary use). Conventional foods include whole foods like garlic, nuts, and tomatoes. Modified foods are those that have been enriched, enhanced, or fortified. Examples of these would be calcium-fortified orange juice, folate-enriched bread, or energy bars. Medical foods are those that serve medical purposes and those for dietary use include products like lactose-free milk or gluten-free breads.  Currently, although there are no specific regulations in the U.S. regarding functional foods, FDA standards must be followed for how a product is marketed (e.g., as a food additive, conventional food, dietary supplement, etc.) and the types of nutrient or health claims that can be made.


Functional foods provide additional nutrients that can improve health and performance.


The FDA does not recognize functional foods as a regulatory product category, although it has drafted guidelines.  Rather, it categorizes so-called functional foods as either a food or a drug, depending on the labeling and claims made by the manufacturer of the specific product, under the Federal Food Drug and Cosmetic Act.  The FDA has approved qualified health claims for some functional ingredients; e.g., diets that include soluble fiber from oats can claim to lower the risk for heart disease. Listed here are health claims that have been approved by the FDA.

There also is no U.S. standard for what are considered “functional ingredients.” These include a broad range of ingredients such as dietary supplements, bioactive plant constituents, antioxidants, dietary fiber, prebiotics, probiotics, lipids, bioactive peptides, vitamins, minerals, and botanicals. Recently, there has been a call for such definitions and for dosing requirements for these ingredients, especially as they relate to performance benefits.

Evidence regarding the impact of functional ingredients on physiological functions is limited. An example of how the data for a few functional ingredients have been evaluated can be viewed in this article. Consult the Natural Medicines Database for information on specific functional ingredients.

When and how much of a functional ingredient a person should consume should be evaluated on an individual basis.


Because regulation is limited, claims of improved performance can be made without verification by scientific evidence or without reporting the amounts of the functional ingredients in a food or beverage. It is important for medical practitioners to review the scientific evidence to determine how much of a supplement is needed to receive the desired benefits. Also, one should pay attention to the other ingredients within the product. Interactions with other ingredients may actually have a negative impact on health and performance. Before altering your diet to include high consumption of any functional food, consult your physician.

Summary for Military Relevance

Functional foods are especially relevant to the health and fitness of the Warfighter, as they are often packaged for easy consumption and fortified/supplemented with multiple nutrients and other ingredients to replace those that a Warfighter might deplete during training. Nutrition tailored to an individual’s activities is essential to performance, and military duties often call for efficient delivery of needed nutrients.

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